Towards a Multi-Criteria Methodology for Assessment of Geological Carbon Storage Options

Carbon capture and storage (CCS) could achieve drastic cuts in the CO₂ emissions associated with fossil fuels in the near to medium term and has been promoted as a significant climate change mitigation option. As the profile of this family of technologies grows rapidly, there remain many uncertainties relating to its viability, effectiveness and desirability. In this paper we begin to map out some of the key issues associated with CCS, using a multi-criteria approach to explore how an (admittedly small) selection of stakeholders perceive alternative storage options and energy scenarios. We present five long-term scenarios describing alternative ways in which the UK energy system could develop and which deploy different levels of carbon storage. The key storage options considered are oil and gas fields (both disused and with enhanced oil recovery), traps in saline aquifers, saline aquifers outside traps and on-shore sites. The relative performance of the scenarios and the storage reservoirs included within them have been assessed against a set of socio-economic, technical and environmental criteria by a small selection of stakeholders to the carbon storage debate. Whilst we cannot make strong conclusions regarding precise stakeholder opinions at this stage due to the small size of the sample, the broad delineation of the arguments for and against CCS are evident. Multi-criteria assessment (MCA) appears to hold much potential as a useful tool for characterising and better understanding differences in stakeholder assessments of CCS and its implications, and for identifying options around which greater consensus on the desirability (or otherwise) of CCS as a mitigation strategy might emerge.